1. Field of the Invention
The present invention relates to a method and apparatus for the treatment of a wiping solution which is employed for cleaning a wiping roller used for wiping off ink.
2. Background Art
A wiping roller for wiping off excess ink that adheres to intaglios placed around an intaglio cylinder of an intaglio printing press is partially immersed in a wiping solution contained in a wiping-solution tank, so that the ink adhering to the immersed portion is dispersed into the solution; and operation can continue for removal of excess ink from the intaglio cylinder. When such a wiping solution containing dispersed ink is disposed of without being subjected to any treatment, the solution may cause environmental problems. Therefore, a variety of means for the treatment of such a used wiping solution to enable recycling of the solution have already been proposed.
For example, Japanese Patent Application Laid-Open (kokai) No. 10-85789 discloses a method for the treatment of a used wiping solution. In the method, a used wiping solution is separated into a transparent solution and a residual solution by use of an ultrafiltration membrane (UF membrane), and the transparent solution is recycled as a raw material of a wiping solution; a flocculant (an alkali salt) is added to the residual solution for flocculation of ink components; the resultant solution is subjected to filtration to thereby produce a solid product and a filtrate; the solid product is disposed of as waste, and the filtrate is neutralized and then separated into a distilled water and a concentrated salt solution through distillation; and the distilled water is recycled as a raw material of the wiping solution, and a portion of the concentrated salt solution is recycled as the flocculant.
However, the method disclosed in Japanese Patent Application Laid-Open (kokai) No. 10-85789 involves the following problems:
(1) since a wiping solution concentrated into the form of slurry is subjected to filtration by use of a UF membrane, pores of the membrane tend to become clogged with the slurry, and thus the membrane must be changed frequently, resulting in laborious operation; and
(2) solutions which are treated in different ways to have different statesxe2x80x94a transparent solution obtained through filtration by use of a UF membrane, distilled water, etc.xe2x80x94are employed as raw materials of a wiping solution, and thus it is difficult to produce a wiping solution having consistent properties.
In view of the foregoing, an object of the present invention is to provide a method and apparatus for the treatment of a wiping solution, which facilitate the treatment of a used wiping solution and enable the production of a wiping solution having consistent properties.
In order to solve the aforementioned problems, the present invention provides a method for the treatment of a wiping solution, which comprises adding a flocculant to a used wiping solution for flocculation of ink contained in the used wiping solution; filtering the used wiping solution for separation of the used wiping solution into sludge and a filtrate; heating the filtrate to produce distilled water and a concentrated solution; returning the distilled water for recycling to serve as a raw material of a wiping solution; and heating the concentrated solution for separation of the concentrated solution into steam and a solid residue.
In order to solve the aforementioned problems, the present invention also provides an apparatus for the treatment of a wiping solution, which comprises ink flocculation means for flocculating ink contained in a used wiping solution by the addition of a flocculant to the used wiping solution; solid-liquid separation means for separating, into sludge and a filtrate, the used wiping solution containing the ink which is flocculated by the ink flocculation means through filtration of the used wiping solution; distilled water production means for producing distilled water and a concentrated solution through heating of the filtrate which is separated by the solid-liquid separation means; water recycling means for recycling the distilled water which is produced by the distilled water production means as a raw material of a wiping solution; and post treatment means for separating the concentrated solution into steam and a solid residue through heating of the concentrated solution which is produced by the distilled water production means.